On Nov. 12, 2008, EPA substantially strengthened the National Ambient Air Quality Standards for lead (see 73 FR 66964). EPA lowered the level of the primary (health-based) standard from 1.5 micrograms per cubic meter (µg/m3) to 0.15 µg/m3, measured as total suspended particles. EPA also revised the secondary (welfare-based) standard to be identical to the primary standard.

The standard is based on the highest rolling three-month average over a period of three years and two months. The standard is met at a monitoring site when the three-month average is less than or equal to 0.15 μg/m3. For specific rules and technical information, consult 40 CFR Pt. 50, Appendix R.

Disclaimer: The following data is calculated using the lead National Ambient Air Quality Standards regulations. Yearly and quarterly data shown below has been subject to data review and validation procedures by the department. Monthly data has been reviewed and verified by the monitoring agency.

Data Table: Updated monthly

The units for all averages in this table are micrograms per cubic meter. Data in this table, is calculated at local conditions using daily average temperature and barometric pressure. Lead is sampled on a set schedule. Results in this table are a combination of samples for this site taken on an every sixth day run schedule.

The units for all averages in this chart are micrograms per cubic meter.